1. Field of the Invention
The present invention relates to novel compounds and methods of using those compounds to treat oncological conditions.
2. Description of the Prior Art
Basic research has recently provided the life sciences community with an unprecedented volume of information on the human genetic code and the proteins that are produced by it. In 2001, the complete sequence of the human genome was reported (Lander, E. S. et al. Initial sequencing and analysis of the human genome. Nature (2001) 409:860; Venter, J. C. et al. The sequence of the human genome. Science (2001) 291:1304). Increasingly, the global research community is now classifying the 50,000+ proteins that are encoded by this genetic sequence, and more importantly, it is attempting to identify those proteins that are causative of major, under-treated human diseases.
Despite the wealth of information that the human genome and its proteins are providing, particularly in the area of conformational control of protein function, the methodology and strategy by which the pharmaceutical industry sets about to develop small molecule therapeutics has not significantly advanced beyond using native protein active sites for binding to small molecule therapeutic agents. These native active sites are normally used by proteins to perform essential cellular functions by binding to and processing natural substrates or tranducing signals from natural ligands. Because these native pockets are used broadly by many other proteins within protein families, drugs which interact with them are often plagued by lack of selectivity and, as a consequence, insufficient therapeutic windows to achieve maximum efficacy. Side effects and toxicities are revealed in such small molecules, either during preclinical discovery, clinical trials, or later in the marketplace. Side effects and toxicities continue to be a major reason for the high attrition rate seen within the drug development process. For the kinase protein family of proteins, interactions at these native active sites have been recently reviewed: see J. Dumas, Protein Kinase Inhibitors: Emerging Pharmacophores 1997-2001, Expert Opinion on Therapeutic Patents (2001) 11: 405-429; J. Dumas, Editor, New challenges in Protein Kinase Inhibition, in Current Topics in Medicinal Chemistry (2002) 2: issue 9.
It is known that proteins are flexible, and this flexibility has been reported and utilized with the discovery of the small molecules which bind to alternative, flexible active sites with proteins. For review of this topic, see Teague, Nature Reviews/Drug Discovery, Vol. 2, pp. 527-541 (2003). See also, Wu et al., Structure, Vol. 11, pp. 399-410 (2003). However these reports focus on small molecules which bind only to proteins at the protein natural active sites. Peng et al., Bio. Organic and Medicinal Chemistry Ltrs., Vol. 13, pp. 3693-3699 (2003), and Schindler, et al., Science, Vol. 289, p. 1938 (2000) describe inhibitors of abl kinase. These inhibitors are identified in WO Publication No. 2002/034727. This class of inhibitors binds to the ATP active site while also binding in a mode that induces movement of the kinase catalytic loop. Pargellis et al., Nature Structural Biology, Vol. 9, p. 268 (2002) reported inhibitors p38 alpha-kinase also disclosed in WO Publication No. 00/43384 and Regan et al., J. Medicinal Chemistry, Vol. 45, pp. 2994-3008 (2002). This class of inhibitors also interacts with the kinase at the ATP active site involving a concomitant movement of the kinase activation loop.
More recently, it has been disclosed that kinases utilize activation loops and kinase domain regulatory pockets to control their state of catalytic activity. This has been recently reviewed (see, e.g., M. Huse and J. Kuriyan, Cell (2002) 109:275).